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• avcodec/dxa : use uint8_t for type of arrays

  24 septembre 2023, par Paul B Mahol

  avcodec/dxa : use uint8_t for type of arrays
  

  • [DH] libavcodec/dxa.c

• doc/examples/output : Cast pointer to the right (const) type

  22 avril 2017, par Diego Biurrun

  doc/examples/output : Cast pointer to the right (const) type
  doc/examples/output.c:512:33 : warning : passing argument 2 of ‘sws_scale’ from incompatible pointer type
  

  • [DBH] doc/examples/output.c

• Python asyncio subprocess code returns "pipe closed by peer or os.write(pipe, data) raised exception."

  4 novembre 2022, par Duke Dougal

  I am trying to convert a synchronous Python process to asyncio. Any ideas what I am doing wrong ?

  


  This is the synchronous code which successfully starts ffmpeg and converts a directory of webp files into a video.

  


  import subprocess
import shlex
from os import listdir
from os.path import isfile, join

output_filename = 'output.mp4'
process = subprocess.Popen(shlex.split(f'ffmpeg -y -framerate 60 -i pipe: -vcodec libx265 -pix_fmt yuv420p -crf 24 output.mp4'), stdin=subprocess.PIPE)

thepath = '/home/ubuntu/webpfiles/'
thefiles = [f for f in listdir(thepath) if isfile(join(thepath, f))]
for filename in thefiles:
    absolute_path = f'{thepath}{filename}'
    with open(absolute_path, 'rb') as f:
        process.stdin.write(f.read())

process.stdin.close()
process.wait()
process.terminate()


  


  This async code fails :

  


  from os import listdir
from os.path import isfile, join
import shlex
import asyncio

outputfilename = 'output.mp4'

async def write_stdin(proc):
    thepath = '/home/ubuntu/webpfiles/'
    thefiles = [f for f in listdir(thepath) if isfile(join(thepath, f))]
    thefiles.sort()
    for filename in thefiles:
        absolute_path = f'{thepath}{filename}'
        with open(absolute_path, 'rb') as f:
            await proc.communicate(input=f.read())

async def create_ffmpeg_subprocess():
    bin = f'/home/ubuntu/bin/ffmpeg'
    params = f'-y -framerate 60 -i pipe: -vcodec libx265 -pix_fmt yuv420p -crf 24 {outputfilename}'
    proc = await asyncio.create_subprocess_exec(
        bin,
        *shlex.split(params),
        stdin=asyncio.subprocess.PIPE,
        stdout=asyncio.subprocess.PIPE,
        stderr=asyncio.subprocess.PIPE,
    )
    return proc

async def start():
    loop = asyncio.get_event_loop()
    proc = await create_ffmpeg_subprocess()
    task_stdout = loop.create_task(write_stdin(proc))
    await asyncio.gather(task_stdout)

if __name__ == '__main__':
    asyncio.run(start())


  


  The output for the async code is :

  


  pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.
pipe closed by peer or os.write(pipe, data) raised exception.


  


  etc - one line for each webp file